1. Field of the Invention
Embodiments of the present invention relate generally to systems and methods with reservoirs and, in specific embodiments, to a system with a reservoir and a plunger that are shaped to limit a presence of air bubbles in a fluidic medium expelled from the reservoir.
2. Related Art
According to modern medical techniques, certain chronic diseases may be treated by delivering a medication or other substance to the body of a patient. For example, diabetes is a chronic disease that is commonly treated by delivering defined amounts of insulin to a patient at appropriate times. Traditionally, manually operated syringes and insulin pens have been employed for delivering insulin to a patient. More recently, modern systems have been designed to include programmable pumps for delivering controlled amounts of medication to a patient.
Pump type delivery devices have been configured in external devices, which connect to a patient, and have also been configured in implantable devices, which are implanted inside of the body of a patient. External pump type delivery devices include devices designed for use in a stationary location, such as a hospital, a clinic, or the like, and further include devices configured for ambulatory or portable use, such as devices that are designed to be carried by a patient, or the like. External pump type delivery devices may be connected in fluid flow communication to a patient or user, for example, through a suitable hollow tubing. The hollow tubing may be connected to a hollow needle that is designed to pierce the skin of the patient and to deliver a fluidic medium there-through. Alternatively, the hollow tubing may be connected directly to the patient as through a cannula, or the like.
Examples of some external pump type delivery devices are described in the following references: (i) Published PCT Application WO 01/70307 (PCT/US01/09139), entitled “Exchangeable Electronic Cards for Infusion Devices”; (ii) Published PCT Application WO 04/030716 (PCT/US2003/028769), entitled “Components and Methods for Patient Infusion Device”; (iii) Published PCT Application WO 04/030717 (PCT/US2003/029019), entitled “Dispenser Components and Methods for Infusion Device”; (iv) U.S. Patent Application Pub. No. 2005/0065760, entitled “Method for Advising Patients Concerning Doses Of Insulin”; and (v) U.S. Pat. No. 6,589,229, entitled “Wearable Self-Contained Drug Infusion Device”, each of which is incorporated by reference herein in its entirety.
As compared to syringes and insulin pens, pump type delivery devices can be significantly more convenient to a patient, in that doses of insulin may be calculated and delivered automatically to a patient at any time during the day or night. Furthermore, when used in conjunction with glucose sensors or monitors, insulin pumps may be automatically controlled to provide appropriate doses of a fluidic medium at appropriate times of need, based on sensed or monitored levels of blood glucose. As a result, pump type delivery devices have become an important aspect of modern medical treatments of various types of medical conditions, such as diabetes, and the like. As pump technologies improve and doctors and patients become more familiar with such devices, external medical infusion pump treatments are expected to increase in popularity and are expected to increase substantially in number over the next decade.